steel door frame

例句：

1. 1. The new steel door frame is sturdy and secure.
   新的钢制门框坚固且安全。
2. 2. The steel door frame was installed by a professional team.
   钢制门框由专业团队安装。
3. 3. The steel door frame provides excellent protection against intruders.
   钢制门框能有效防止入侵者。